imp a small, mischievous devil or sprite. The word is recorded in Old English (in form impa, impe) in the sense ‘young shoot, scion’, impian ‘to graft’, based on Greek emphuein ‘to implant’. In late Middle English, the noun denoted a descendant, especially of a noble family, and later a child of the devil or a person regarded as such; hence a ‘little devil’ or mischievous child (early 17th century).

The verb imp in falconry, meaning repair a damaged feather in (the wing or tail of a trained hawk) by attaching part of a new feather, retains the original meaning ‘to graft’.

imp †young shoot, sapling OE.; offspring, child XIV; ‘child’ of the Devil, evil spirit XVI; mischievous child XVII. OE. impa or impe.
So imp vb. †graft, engraft OE.; engraft feathers in a bird's wing so as to improve or restore its flight XV; enlarge, eke out XVI. OE. impian, corr. to OHG. impfōn (G. impfen), shortened analogues of OHG. impitōn (MHG. impfeten) — Rom. *impotare, f. medL. impotus graft — Gr. émphutos implanted, engrafted, vbl. adj. of emphúein implant, f. EM-2 + phúein (see BE C).

imp / imp/ • n. a mischievous child: a cheeky young imp. ∎  a small, mischievous devil or sprite.• v. [tr.] repair a damaged feather in (the wing or tail of a trained hawk) by attaching part of a new feather.

IMP Acronym for interface message processor. One of the switching computers that together formed the backbone network for the ARPANET.

IMP / imp/ • abbr. Bridge International Match Point.